Health care costs could rise an additional $8.4 million, representing an approximate 0.13-percent increase, if the U.S. Department of Defense allows transgender people to serve openly in the military, a new study commissioned by the Pentagon reveals.

The RAND Corporation, a non-profit research group, says its estimate comes as the nation's military agency reviews its policy on allowing transgender personnel to serve openly and receive gender transition-related treatment during military service.

The study says the number of transgender individuals currently serving is between 1,320 and 6,630 out of a total of about 1.3 million service members.

If an open policy is adopted, between 30 and 140 new hormone treatments could be initiated a year and 25 to 130 gender transition-related surgeries could be utilized a year, RAND concludes. That would mean additional health care costs could range between $2.4 million and $8.4 million.

Eighteen countries allow transgender personnel to serve openly in their militaries, including Australia, Canada, Israel and the United Kingdom.

Health care costs could skyrocket to an annual $8.4 million if the U.S. Department of Defense allows transgender people to serve openly in the military, a new study commissioned by the Pentagon reveals.